The goal of computer-assisted surgery is to provide the surgeon with guidance during an intervention using augmented reality (AR). To display preoperative data correctly, soft tissue deformations that occur during surgery have to be taken into consideration. Optical laparoscopic sensors, such as stereo endoscopes, can produce a 3D reconstruction of single stereo frames for registration. Due to the small field of view and the homogeneous structure of tissue, reconstructing just a single frame in general will not provide enough detail to register and update preoperative data due to ambiguities. In this paper, we propose and evaluate a system that combines multiple smaller reconstructions from different view points to segment and reconstruct a large model of an organ. By using GPU-based methods we achieve near real-time performance. We evaluated the system on an ex-vivo porcine liver (4.21mm ± 0.63) and on two synthetic silicone livers (3.64mm ± 0.31 and 1.89mm ± 0.19) using three different methods for estimating the camera pose (no tracking, optical tracking and a combination).